Borescope



J. W. LAN G BORESCOPE April 20, 1965 2 Sheets-Sheet 1 Filed March 31. 1961 Ill www. M

INVENTOR JOHN W. I4/V64 BY A r ORNEYS United States Patent() 3,178,994 BORESCOPE John W. Lang, Dewey Road, Cheltenham, Pa. Filed Mar. 31, 1961, Ser. No. 99,947 1 Claim. (Cl. 88-14) The present invention relates to borescopes of the character which are utilized to inspect spaces or chambers, such as cylinders of internal combustion engines, combustion chambers in jet aircraft, turbine housings and blades, gun bores, tubes, reaction vessels and chambers of all kinds.

A purpose of the invention is to permit scanning a band or zone of the wall of a chamber by precise control of the area of inspection from outside the chamber, as by adjusting the angle of the borescope mirror from the position of the observer.

A further purpose is to permit an observer to loca-te an area under a low degree of magnification in use of a borescope and then to zoom, and inspect the same locality under a higher magnification.

A further purpose is to obtain a more intense illumination yof the walls of a chamber by use `of a quartz incandescent lamp containing iodine vapor.

A further purpose is to provide both a scanning control and a zooming control on a borescope.

A further purpose is to employ the borescope housing and the tube supporting the objective lens in order to carry electric current for operation of the illuminator lamp.

Further purposes appear in the specification and in the claims.

In the prior art a wide angle borescope is in existence which permits inspection of large areas of chambers axially ahead of and behind the position of the borescope mirror, but the electiveness of this device has been seriously limited because the image is so fuzzy and the magnitication so poor that little can be learned of the detail. Efforts have been made to provide auxiliary sources of illumination but these have been rather unsatisfactory. j

Borescopes'have also been produced which permit inspection of a small area of the cavity at high magnification but they are very tedious to operate since it is necessary to withdraw the instrument and reset the mirror each time the area of vision is changed. The settings of the mirror are so critical from the standpoint of the light lever that it is possible to miss entirely signicant areas of the cavity and it is ditiicult for the observer to know exactly what he is looking at.

The present invention provides a borescope of greatly improved usefulness.

The user is able to adjust the angle of the mirror slowly or rapidly as desired without changing the over-all position of the borescope.

Once the area of inspection appears to be of particular interest, the user is able to zoom to a higher magnication and inspect a certain area within a relatively larger area at this higher magnification. The user can scan the area being inspected at either the higher or the lower magnication as desired.

Extremely high intensity of illumination is provided by incorporating at the forward end of the borescope a quartz envelope incandescent lamp which contains iodine vapor to continuously remove spatter from the tungsten filament which deposits on the envelope and redeposit this spatter on the filament. It is therefore possible to operate at Very high electrical energy levels and obtain intense illumination. A commercial lamp of this kind is available known as the Quartzline.

In the drawings I have chosen to illustrate one only of the numerous embodiments in which my invention may appear, selecting the form shown from the standpoints of convenience in illustration, satisfactory operation and clear demonstration of the principles involved.

FIGURE l is a fragmentary side elevation of a borescope of the invention.

FIGURE 2 is an enlarged axial section of the forward portion of the borescope of FIGURE l with the mirror adjusted to one position.

FIGURE 3 is a fragmentary view similar to FIGURE 2 showing the mirror adjusted to a different angular position.

FIGURE 4 is a view similar to FIGURE 2 showing an intermediate portion of the borescope of the invention.

FIGURE 5 is a view similar to FIGURE 2 showing the rearward or operators end of the borescope of the invention.

Describing in illustration but not in limitation and referring to the drawings:

A borescope comprises a metallic housing 29 which at the forward end has a metallic nose 21 anchored by screws 22. Rearward of the nose there is an illumina-tor window 23 which allows light from a quartz envelope iodine process tungsten filament incandescent lamp 24 to illuminate the interior of the cavity being inspected. The nose has a lamp socket opening 25 which receives one lamp terminal 26 and makes connection by set screw 27. Rearward of the lamp and inside the housing there is Van insulating tubular bushing 2S within which is mounted a metallic Contact element `30 which has a terminal opening 31 which receives opposing terminal 32 of the lamp. The bushing 2S is held in place by set screw 33 in the contact element 3@ and the terminal 32 is engaged by set screw 34 in contact element 39. A anged insulating bushing 35 is around a reduced forward end of the contact element 30 and is held in place by metallic ring 36 and screws 37.

Rearward of the illuminator window 23 the housing 20 has at the same side an inspection window 38. Within the housing, mounted on pivot 4% is a mirror 41 which is shiftable in angular position .with respect to the axis of the housing. The mirror has an actuator pin 4Z on its mounting remote from the pivot which engages in a slot 43 of metallic slider 44 which is guided and contacted by the electrical contact element 30 at one end at 45 and is guided at the opposite end at 46 by reduced diameter end lens mounting porti-on 47 of metallic tube 4S which extends longitudinally through the housing in spaced relation from it, being kept out of electrical contact at the forward end by insulating sleeve 28 and being kept out of electrical contact at the rearward end by the insulating sleeve 50, as best seen in FGURE 5.

The tube 48 has on its outside near its forward end a cam track 51 which receives follower pin 52 on slider 44.

At the rearward end secured to the tube 48 is a rotatable scanning adjustment handle 53 under the control of the operator, so that by turning the handle 53 the bushing and the tube 48 suitably secured together will turn. The interconnection between the tube 48 and the rotatable scanning handle 53 is conveniently made by insulating bushing 54, FIGURE 5, which receives screw 55 and extends through slot 56 of the handle 53, slot 57 of the bushing Si) and slot 58 of the tube 4S, in line with one another.

In the forward end of the metallic tube 48 is secured by a suitable mounting an objective lens 6i) of the optical system which extends through the housing and receives light from the mirror 41. As shown, objective lens 66 is suitably immovable axially although it rotates with rthe tube 48.

Within the tube 4S, and slidable axially with respect to it, is a zoom tube 61 which mounts a field lens system,

consisting of a field lens 62 and relay lenses 63 and 64 as well known in Athe art. The system of mounting suitably includes iianging the forward end of the tube 61 at 65 and employing spacer tubes 66, 67 and 68 to position the respective lenses, as Well known in the art. The zoom tube 61 has an opening through which the bushing 54 passes and the screw 55 through the bushing passes through and is anchored in slidable zoom control 7 0 which is around the outside or rotatable scanning handle 53. By pulling on the slidable Zoo-m control 70 it is possible to shift the magnification from high magnification to low magnification, suitably by a multiple of three. Thus, the magnification of the device for general inspection may be one, and for close-up Iinspection may be three.

The mirror scanning control 53 has helical thread 71 on the interior which receives a thread engaging pin 72 of eyepiece lens system tube 73 which mounts eyepiece lenses 74, 75 by means of suitable force iit tubes 76, 77 and a suitable eyepiece 78 which is threaded on the outside.

A metallic electric plug connector 80 is threaded at 81 into the housing 20 through an inner collar 82 and an outer collar 83. Within the outer collar 83, and axially between a shoulder thereon and inner collar 82 is a bearing ring 84 which is secured by suitable screws not shown to mirror scanning control 53. Within the plug connector 88 there is an insulating lbushing 85 which provides a chamber 86 in which is provided contact 87 engaging the outside of metallic tube 48, metallic connector spring 88, pigtail 89 and terminal element 90 working against the opposite end and engaging one of the elements of the plug.

A suitable electric plug and extension cord 91 connect to the plug connector.

In operation, once the device is assembled, the forward end of the borescope is placed in the cavity which is to undergo inspection. Light from the lamp 24 is received by the mirror and passes through the optical system. The user will first adjust the zoom to give low magnification by moving the slider 70 to the position in which the field lens system is farthest from the objective lens system. The user will scan by turning the scanning handle 53. When an area is encountered which it is desirable to inspect more fully, the user will move the zoom slider 70 to a high magnification in which the field lens system is closer to the objective lens and will span in th high magnification. The user will shift from high to low magnification as desired,

Of course the user will adjust the eyepiece lenses to his eye by turning the eyepiece.

Although a considerable amount of heat is developed by Ithe intense illumination, this does not interfere with operation of the device, since a considerable area of electrical conduction is provided by using the housing 20 and the tube 48 as conductors.

In view of my invention and disclosure, variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benefits of my invention without copying the structure shown, and I, therefore, claim all such insofar as they fall within the reasonable spirit and scope of my claim.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

In a borescope, a housing, a mirror at the forward end of the housing, a tube extending through the housing, a handle connected to the rearward end of the tube adapted to manipulate the said tube, an objective lens at the forward end of the tube, the tube being rotatable with respect to the housing, cam means at the forward end of the tube, pivot Imeans mounting the mirror, a follower engaging the cam means, a slider interconnected with the follower, an actuator pin on the mirror remote from the pivot interconnected with the said slider, a second tube Within the iirst tube, a field lens system mounted on the second tube, there being a slot through the housing and the lirst tube near the rearward end of the borescope, a second slider around the housing at the slot, an actuator extending from the said second slider through the slot to the second tube and permitting change of the longitudinal position of the field lens system With respect to the objective lens and an eyepiece lens system at the rear of the housing.

References Cited by the Examiner UNlTED STATES PATENTS 1,091,933 3/14 Humbrecht 88-57 1,879,412 9/32 Mueller 88-57 2,028,430 1/36 Baddorf et al. 88-71 2,479,792 8/49 Tackaberry 88-57 X 2,541,976 2/51 Bogart 88-14 2,665,617 1/54 Marcouiller 95-11 2,817,754 .l2/57 Moore 88-71 2,899,856 8/59 Shull 88-14 3,090,378 5/63 Sheldon et al. 88-1 3,096,756 7/ 63 Rosenfeld et al 88-14 X JEWELL H. PEDERSEN, Primary Examiner, WILLIAM MISIEK, Examiner,

were* 

